just bought a imac 27 2017 and what is the best os for it?

[Knockoutjosie]

right now im running 48gb of ram, 2 sticks are the 8gb 2400hz and the other 2 are 32gb 3200hz. i did see all 4 stickes combined the speeds are 2400hz. Before i added apples 16gm of ram sticks i saw they were running 3200hz. should i just 2 more 2x16gb of ram sticks?

my specs are
3.4 GHz Intel Core i5

also what is the best os software? right now im running mojave but visual studio code and chrome are saying in the future they will not be supported.

 

[Bigwaff]

also what is the best os software?

The latest macOS supported by your 2017 iMac is macOS 13 Ventura. You should have no problems given the amount of RAM you have installed. What type of storage do you have? SSD? HDD? Fusion Drive? If HDD or Fusion Drive, you should really consider swapping in an SSD. HDD are super slow while Fusion Drives are known to fail after 5 yrs or so.. right about now.

 

[Juicy Box]

If you plan on using any 32bit apps, Mojave was the final MacOS version with 32bit support.

It is so easy to have multiple boot drives with MacOS, you could try a few different versions and see which one works best for what you do with it.

Even if you do 32bit SW on occasion, you can have a separate partition just with Mojave for the times you need the 32bit apps.

 

[Knockoutjosie]

The latest macOS supported by your 2017 iMac is macOS 13 Ventura. You should have no problems given the amount of RAM you have installed. What type of storage do you have? SSD? HDD? Fusion Drive? If HDD or Fusion Drive, you should really consider swapping in an SSD. HDD are super slow while Fusion Drives are known to fail after 5 yrs or so.. right about now.

How can I check what type of storage I have ?

 

[Knockoutjosie]

If you plan on using any 32bit apps, Mojave was the final MacOS version with 32bit support.

It is so easy to have multiple boot drives with MacOS, you could try a few different versions and see which one works best for what you do with it.

Even if you do 32bit SW on occasion, you can have a separate partition just with Mojave for the times you need the 32bit apps.

I don’t believe I use any 32 bit apps at the moment

 

[Juicy Box]

How can I check what type of storage I have ?

Click on the Apple at the upper left side of the screen, then click on "About this Mac".

The window that opens defaults to the "Overview" tab, click on the "Storage".

It should let you know what type of storage the boot drive currently is.

You can also look in the Disk First Aid app in the Utilities Folder if you cannot find your answer in the About this Mac screen.

I don’t believe I use any 32 bit apps at the moment

As long as you are not currently using a HDD or Fusion Drive as your boot drive, I would just install the most recent OS that the Mac Supports. If you are using a HDD or Fusion Drive, I would stick with Mojave.

If you stick with Mojave, I would download Firefox for a more secure web browser, as Apple hasn't updated Safari in Mojave in a few years.

BTW, I agree with @Bigwaff about the switching to a pure SSD if using a HDD or Fusion Drive as the boot drive. While it would better to replace the HDD with a SATA SSD, there is no need to do that if you don't want to mess around with opening the iMac. You can use an external SSD over USB or TB3. Maybe pick one up during the good holiday deals.

 

[Juicy Box]

Another thought, unlike iOS, it is possible to go back to an earlier OS version if you install a newer one and you don't like it. Don't feel like once you install, you are stuck.

So, if you don't like the newer OS or have issues with it, you can always go back.

If you are using a HDD or Fusion Drive, I would stick with Mojave.

Maybe I should explain my reasoning for this.

APFS seems to suck for HDDs and Fusion Drives, and this seemed to have gotten worse with each MacOS version released, while it still kind of sucks on Mojave, it got a lot worse on Catalina, which is why a lot of people with Fusion Drives downgraded to Mojave or High Sierra.

 

[Steve121178]

Ventura will run just fine on a 2017 iMac. Installing older unsupported OS's put you at risk, plus many apps will only support the previous 3 versions of macOS only, so even Big Sur is now cut off from Adobe CC & Microsoft 365. And Catalina is the cut off if you want to use Chrome based browsers FYI. Go with Ventura.

 

[SalisburySam]

My 2017 27” iMac came with Mojave and worked very, very well. Because of new software incompatibility, I had to leave Mojave behind and I upgraded to Monterey. It’s working ok, no issues really. I’ve not gone further and likely won’t as long as Monterey is fully supported and no apps require anything newer. I saw nothing compelling about Ventura, though I may have to get it at some point. The latest macOS, Sonoma, will not work on our 2017 iMacs.